[PATCH] net: eth-phy: Handle gpio_request_by_name() return value

[Ramon Fried]

On Sat, Nov 13, 2021 at 4:23 AM Marek Vasut <marex at denx.de> wrote:
>
> The gpio_request_by_name() returns zero in case of success, however the
> conditional return value check in gpio_request_by_name() checks only for
> (ret != -ENOENT) and if the condition is true, returns ret outright.
>
> This leads to a situation where successful gpio_request_by_name() return
> leads to immediate successful eth_phy_of_to_plat() return as well, and
> to skipped parsing of "reset-assert-us" and "reset-deassert-us", so the
> PHY driver operates with valid reset GPIO, but with assert/deassert times
> set to default, which is 0, instead of the values from DT. This breaks
> PHY reset.
>
> Fix this by checking if return value is non-zero and then for this one
> single allowed non-zero return value, -ENOENT.
>
> Signed-off-by: Marek Vasut <marex at denx.de>
> Cc: Ramon Fried <rfried.dev at gmail.com>
> ---
>  drivers/net/eth-phy-uclass.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/eth-phy-uclass.c b/drivers/net/eth-phy-uclass.c
> index c04bab944d6..a9b358ee234 100644
> --- a/drivers/net/eth-phy-uclass.c
> +++ b/drivers/net/eth-phy-uclass.c
> @@ -138,7 +138,7 @@ static int eth_phy_of_to_plat(struct udevice *dev)
>         ret = gpio_request_by_name(dev, "reset-gpios", 0,
>                                    &uc_priv->reset_gpio,
>                                    GPIOD_IS_OUT);
> -       if (ret != -ENOENT)
> +       if (ret && ret != -ENOENT)
>                 return ret;
>
>         uc_priv->reset_assert_delay = dev_read_u32_default(dev, "reset-assert-us", 0);
> --
> 2.33.0
>
Reviewed-by: Ramon Fried <rfried.dev at gmail.com>